Pushbutton-controlled overload circuit breaker



Feb. 28, 1967 J. ELLENBERGER 3,307,124

PUSHBUTTON-CONTROLLED OVERLOAD CIRCUIT BREAKER Filed June 24, 1965 4Sheets-Sheet 1 WNTORHEIS Feb. 28, 1967 J. ELLENBERGER 3,307,124

PUSHBUTTON-CONTROLLED OVERLOAD CIRCUIT BREAKER Filed June 24, 1965 4Sheets-Sheet 2 INVENTOR; M05 ELLENBERGE/g" Feb. 28, 1967 J. ELLENBERGER3,307,124

PUSHBUTTON-CONTROLLED OVERLOAD CIRCUIT BREAKER Filed June 24, 1.965 4SheetsSheet 3 BNVENTOR JHKOB ELLE/VBERGER MMW00W Feb. 28, 1%? J.ELLENBERGER 330579124 PUSHBUTTON-CONTROLLED OVERLOAD CIRCUIT BREAKER Filed June 24, 1965 4 Sheets-Sheet 4.

INVENTORJHKOB ELLENBERGER g7 a W United States Patent Office 3,307,124PUSHBUTTON-CONTROLLED ()VERLOAD CIRCUKT BREAKER Jakob Ellenberger,Aitdorf, near Nurnberg, Germany, as-

signor to Ellenberger & Poensgen G.m.b.H., a German firm Filed June 24,1965, Ser. No. 466,533 Claims priority, application Germany, June 30,1964, E 27,312 7 Claims. (Cl. 33535) The present invention relates to apushbutton-controlled overload circuit breaker for high rated currentswhich is provided with a thermal and electromagnetic release and with atrip-free release and, if desired, with a manual release.

The known overload circuit breakers of this type have the disadvantageof being of a relatively complicated design and large size and oflasting only for a short time since, even though they break the circuitinstantaneously, they do not also close the circuit instantaneously andtheir contacts are therefore burned off very soon.

It is an object of the present invention to provide an overload circuitbreaker of the above-mentioned type which overcomes these disadvantagesof the known circuit breakers and is designed so as to be easilymanufactured and installed, to occupy a very small space, to have a longservice life, and to be insensitive to shocks, vibrations, andaccelerations so as to render it suitable especially for use in avehicle.

For attaining this object, the invention provides the circuit breakerwith two current conductors which are located within the same plane andmay be electrically connected with each other by a contact bridge whichis movable vertically thereto and forms a substantially Q? shaped loopin which the core of the magnet for the electromagnetic release of thecircuit breaker is provided and which is connected in parallel to thebimetal strip for the thermal release. The circuit breaker according tothe invention is further provided between the loop and the contactbridge with a two-armed lever which is connected to the pushbutton whenthe latter is being depressed and the pivot pin of which is slidablewithin slots in the direction of movement of the pushbutton and is alsopivotable within these slots. By an engagement of a pawl with this pivotpin, this lever may be arrested in a position in which its arm facingthe contact bridge will press the contact bridge against the two currentconductors by means of a spring which acts upon the other arm of thetwo-armed lever.

The substantially Q -shaped loop of the circuit breaker according to theinvention forms the winding of the electromagnet, the magnet core ofwhich is provided within the loop. This permits the circuit breaker tobe made of a very small size. This small size is further due to the factthat the bimetal strip is connected in parallel to the loop, sincewithin the area of the bimetal strip the loop is electrically designedso that, when heated and thereby bent, the bimetal strip will effect thedesired thermal release. By the provision of a contact bridge, the makeand break effects are distributed to and taken up by two connectingpoints. For attaining a trip-free release, the overload circuit breakeraccording to the invention is provided with a two-armed lever which forthe purpose of saving in space is located between the loop and thecontact bridge and is pivotable and slidable in the direction ofmovement of the pushbutton and .also adapted to be connected to thepushbutton when the latter is being depressed to the on position. Thisconnection between the pushbutton and the two-armed lever is againsevered 3,367,124 Patented Feb. 28, 1967 when the pushbutton is fullydepressed. Therefore, when the pushbutton is in the on position, it isno longer connected to the two-armed lever and when the contact bridgeis in the on position, this lever is then merely held by the pawl.Consequently, when the pawl is released by a thermal or electromagneticaction, the twoarmed lever and thus also the contact bridge may moveindependently of the pushbutton and thus permit a tripfree release ofthe circuit breaker.

For reducing the size of the circuit breaker to a further extent, thepawl may in its locking position engage directly upon the armature ofthe electromagnetic release which is acted upon by the bimetal strip. Arelatively small force will then suflice in order to pivot the armatureto its inactive position. This permits an extremely rapid release of thecircuit breaker by means of such small forces that the magnetic systemof the electromagnetic release may be made of a relatively small size.

Another feature of the invention consists in providing the arm of thetwo-armed lever which faces the loop with at least one projection whichextends in the direction toward the current conductors and is providedwith a recess which, when the contact bridge is in the on position, islocated outside of the path of movement of a catch on a control rodwhich is rigidly secured to the pushbutton and preferably provided witha longitudinal slot along which it is guided on the pivot pin of thepawl. When the contact bridge is in its off position in which thementioned arm of the two-armed lever engages upon a stop, the recess inthe projection on this .arm is located within the path of movement ofthis catch. In the off position, this arm of the two-armed lever whichfaces the loop therefore engages upon a stop, and the pivot pin of thetwo-armed lever engages upon the upper end of the guide slots so thatthe two-armed lever will then be in an inclined position, while when thelever is in the on position, it will be in a horizontal position inwhich it cannot be acted upon by the catch on the control rod so thatthe trip-free release will then be possible. If the pushbutton isdepressed when the contact bridge is in its off position, the two armedlever will be taken along by the catch on the control rod and the pivotpin of this lever pivots the pawl to its locking position. When thefinger is then taken off the pushbutton, the pivot pin of the two-armedlever engages against the pawl. As soon as the catch on the control roddisengagcs from the recess in the projection on the two-armed lever, thelatter is suddenly pivoted by spring action which, in turn, causes thecontact bridge to be suddenly moved to its on position. Due to thisrapid connecting movement, the switch contacts of the circuit breakeraccording to the invention will be protected and the circuit breakerwill remain properly operative for a very long time. The manner ofguiding the control rod by means of a slot on the pivot pin of the pawlhas the advantage that the pushbutton and the control rod will be verysimply prevented from turning.

The contact bridge may be secured to a slide member which is acted uponby a disconnecting or release spring and is provided with an aperture orrecess into which the other arm of the two armed lever engages. When thecircuit breaker is in its on position, this arm engages upon the lowerend of the aperture or recess against the action of the release spring,and when the circuit breaker moves to its off position, this arm engagesunder the action of the spring against the upper end of the aperture orrecess. When the circuit breaker is released, the pawl disengages fromthe pivot pin of the two-armed lever so that the spring which acts uponthe arm of the lever which faces the loop presses this arm against itsassociated stop and the entire two-armed lever is thereafter pivotedabout this stop. During this pivoting movement, the

other arm of the two-armed lever which faces the contact bridge hitsagainst the upper end of the aperture or recess in the slide membercarrying the contact bridge and thereby supports and increases theaction of the release spring and accelerates the disconnecting movementof the contact bridge.

For simplifying the manufacture, assembly, and installation of theswitch mechanism of the circuit breaker, this mechanism is preferablymounted within a metal frame which is provided on the upper side fromwhich the pushbutton projects with an insulating plate which is securedto the base of the circuit breaker by means of bolts which also securethe current conductors to the base.

In order to prevent the circuit breaker from being accidentally releaseddue to impacts, strong vibrations, shocks or accelerations which mayoccur, for example, if the circuit breaker is installed in a vehicle, itis provided with a pair of manual release knobs which are mounted on theinsulating plate at the opposite sides of the pushbutton so as to beslidable toward each other in a direction vertical to the axis of thepushbutton, and with a two-armed safety lever which is mounted on theinsulating plate so as to be pivotable against the action of a returnspring about the axis of the pushbutton. One arm of this safety lever isprovided with an end surface which in the neutral position of this leveris located Within the path of movement of a pin on one of the manualrelease knobs and thus prevents this knob from being moved and the pinthereon from acting upon the armature, while the other arm of this leveris provided with an inclined slot into which the pin engages which issecured to the other manual release knob. This construction has theadvantage that it permits the circuit breaker to be released only ifboth manual release knobs are actuated simultaneously. If only one ofthese release knobs is actuated, for example, the knob which acts uponthe armature, its release pin will hit against the end surface of thefirst arm of the safety lever and thus prevent this knob from moving. Ifonly the other manual release knob is actuated, the safety lever willmerely be pivoted without affecting the first knob. If, however, bothknobs are moved simultaneously toward each other, the two-armed safetylever will first be pivoted about the axis of the pushbutton by theknob, the pin of which slides along the slot in the one arm of the leverso that the end surface of the other arm of the lever will movelaterally away from the pin on the other knob which acts upon thearmature so that this knob will then be free to be moved so as to effectthe manual release of the circuit breaker.

In order to prevent the armature of the electromagnetic release alsofrom being affected by strong vibrations, impacts, shocks, oraccelerations, this armature is provided in the form of a two-armedlever, one arm of which when in the attracted position nearly closes themagnetic circuit between the magnet core and a magnet yoke which ispivotable with considerable friction on the magnet core, While the otherarm of this lever is substantially U-shaped and one side wall of the Uis adapted to hold the pawl in its locking position, while the otherside wall of the U may be acted upon by. the pin on the manual releaseknob which is associated with the mentioned end surface of the safetylever.

Since the armature forms a two-armed lever, it may be designed so thatits center of gravity is located at or near its pivot point. Thisconstruction prevents the armature from being pivoted as the result ofimpacts, strong vibrations, accelerations or the like, and it insuresthat the armature will only be pivoted at the occurrence of excesscurrents or short circuits.

The features and advantages of the present invention will become moreclearly apparent from the following detailed description thereof whichis to be read with reference to the accompanying drawings, in which-FIGURE 1 shows a side view of a fully enclosed overload circuit breakeraccording to the invention;

FIGURE 2 shows a view of the circuit breaker, as seen from the left ofFIGURE 1;

FIGURE 3 shows a vertical longitudinal section of the circuit breakeraccording to FIGURE 1 in the on position;

FIGURE 4 shows a view of the circuit breaker, as seen from the left ofFIGURE 3, and partly in a vertical section which is taken within a planepassing through the loop of one of the current conductors;

FIGURE 5 shows a vertical section similar to FIGURE 3, but in which thecircuit breaker is shown in the off position;

FIGURE 6 shows a view similar to FIGURE 4, but in which the circuitbreaker is shown in its off position according to FIGURE 5;

FIGURE 7 shows a top View of the circuit breaker according to FIGURES 4and 6, and partly in a section which is taken within a plane passingthrough the two manual release knobs; while FIGURE 8 shows the same topview as in FIGURE 7, but with the two manual release knobs being shiftedto the position toward the pushbutton.

As illustrated in the drawings, the overload circuit breaker accordingto the invention comprises a housing of insulating material whichconsists of a base 1 and a cap 2, and two terminal strips 3 and 4projecting in opposite direction from and between the base 1 and cap 2,and carrying connecting screws 5 with nuts 6 thereon. A pushbutton 7 andtwo manual release knobs 8 and 9 project through the upper side of thehousing 2. At the inside of the housing, the terminal strip 3 continuesas a current conductor 3' which forms a loop 10 in which the core 12 ofan electromagnet is secured by means of a screw 11. This core carries ayoke 14 which is connected to the core 12 by means of a rivet 13 in amanner so as to be pivo ta'ble with such a considerable friction thatits position relative to the core 12 can be changed only by means of asuitable tool. Yoke 14 has an arm 15 which is bent so as to extend inthe direction toward an arm 16 of the armature 17 of the magnet. Yoke 14is pivotable as described for the purpose of adjusting the size of theair gap between the yoke and the arm 16 of the armature 17 and for thusadjusting the electromagnetic release of the circuit breaker. The arm 16of armature 17 has a pair of tabs 18 thereon which are adapted to bedirectly acted upon by a 'bimetal strip 19 which may be U-shaped and thetwo arms of which are secured to the current conductor 3, for example,by being screwed, soldered or welded thereto. The gap 20 in the contactbar 3 underneath the loop 10 is bridged by the bimetal strip 19. Thebimetal strip carries an angular part 21 which engages upon a conicaltip 22 of a setscrew 23. By turning this setscrew 23 it is possible tomove the bimetal strip 19 more closely toward or farther away from thetabs 18 on the arm 16.

The armature 17 is pivotably mounted on a pin 24 which is secured withina frame 25, and its upper part is U-shaped. One side wall 26 of thisU-shaped part is acted upon in a radial direction of pin 24 by a pawl27, while the other side wall 28 which has an inclined surface 30 may beacted upon by a pin 29 on a manual release knob 8 when the latter isshifted in the direction toward the axis of the push-button 7 so thatthe armature 17 will then be pivoted in a counterclockwise direction, asseen in FIGURE 4, and against the action of a torsion spring 31 which ismounted on pin 24, so that the side wall 26 will then disengage from thepawl 27. One arm of the torsion spring 31 acts upon the side wall 28 ofthe U- shaped part of the armature 17, while the other arm of thisspring acts upon a part 32 of the frame 35.

Pawl 27 is made of sheet metal and bent so as to be substantiallyU-shaped, and it is pivotably mounted on a pin 33 which is secured tothe frame 25. Each of the two parallel arms or walls of pawl 27 isprovided with a detent 34 and a projection 35. By means of the detents34, pawl 27 is adapted to hold a two-armed lever 36 in the horizontalposition as shown in FIGURE 3. The left arm 37 of lever 36 is acted upon'by the upper end of a compression spring 38 which is loosely woundaround a rod on pin 39 which is rigidly secured to a part 40 of frame 25which supports the lower end of spring 38. The arm 37 of lever 36 isprovided on both sides thereof with downwardly projection lugs 41between which the pin 39 with the spring 38 thereon is located. Near itslower end, each of these lugs 41 has a recess 42.

The two current conductors 3' and 4 are provided with fixed contacts 43and 44 which are operatively associated with corresponding contacts on acontact bridge 45 which, when the circuit breaker is in the on positionas shown in FIGURE 3, are in firm engagement with the contacts 43 and44. The contact bridge 45 is secured to a slide member 46 which ismovable in the vertical direction by being guided in apertures in thehorizontal parts 47 and 48 of the frame 25. Slide member 46 is providedwith a recess 49 into which the arm 50 of the two-armed lever 36engages. In the on position of the circuit breaker as illustrated inFIGURE 3, this arm 50 engages upon the lower end 51 of the recess 49.Arm 50 may also cooperate with the upper end 52 of recess 49 in a manneras will be later described.

The two-armed lever 36 is provided with a pair of bent-over tabs 53 inwhich a pivot pin 54 is secured which in the on position of the circuitbreaker as shown in FIGURE 3 engages with the detents 34 on lever 36.This pivot pin 54 is slidable in the vertical direction and alsopivotable in slots 55 in the two side walls 25 and 25" of frame 25.

When the circuit breaker is in the oil? position as shown in FIGURE 5,the arm 37 of the two-armed lever 36 engages upon a stop member 56,while the pivot pin 54 is then in engagement with the upper end of theslots 55.

The pushbutton 7 is provided and preferably integral with a control rod57 of insulating material which has a projection 58 thereon which isadapted to engage into the recesses 42 in the lugs 41 of lever 36. Thepushbutton 7 is acted upon in the usual manner by the upper end of acompression spring 59, the lower end of which is supported on aninsulating plate 60. This insulating plate 60 forms the support on whichthe frame 25 is rigldly secured. The insulating plate 60 as well as thecurrent conductors 3 and 4 are secured by four bolts 61 and nuts 62 tothe base 1 which consists of insulating material. The cap 2 is removablyconnected to the insulating plate 60 by means of a pair of screws 63.

The two slide knobs 8 and 9 for the manual release of the circuitbreaker are slidably mounted in the insulating plate 60. On its lowerside, knob 9 is likewise provided with a pin 29. Each knob 8 and 9 isacted upon by a compression spring 64. A flat plate-shaped lever 65 ismounted on the insulating plate 60 so as to be pivotable about the axisof the control rod 57. One arm of this lever 65 has an end surface 66,while the other arm is provided with an inclined slot 67 into which thepin 29 of the manual release knob 9 engages. When the circuit breaker isin the position as shown in FIGURE 7, the end surface 66 of lever 65 islocated directly in front of the pin 29 of the other manual release knob8 and thus prevents this knob 8 from moving.

The manner of operation of the overload circuit breaker according to theinvention is as follows:

In the event that, when the pushbutton 7 is depressed and the circuitbreaker is in its on position as shown in FIGURES 3 and 4, an excesscurrent occurs, the bimetal strip 19 will be heated and thereby bent andpivoted in the clockwise direction, as seen in FIGURE 4, until itpresses against the tabs 18 on the arm 16 of the armature 17 and pivotsthe latter in the counterclockwise direction. The side wall 26 of thearmature 17 thereby disengages from the pawl 27 so that under the actionof the compression spring 38 on pin 39 and the release spring 46' on theslide member 46, pawl 27 will then be pivoted counterclockwise toits'inactive position as shown in FIG- URE 5. During the upward movementof lever 36, the arm 37 thereof engages upon the stop member 56, asshown in FIGURE 5, so that under the action of the compression spring 38and the release spring 46 the lever 36 will then be pivoted in thecounterclockwise direction about the stop member 56, and the right arm50 of lever 36 will hit against the upper end of the recess 49 in theslide member 46 so that the opening or circuit-breaking movement of thecontact bridge 45 which has already been started by the release spring46' will be accelerated. In this off position of the circuit breakerwhich is shown in FIGURES 5 and 6, the pivot pin 54 engages upon theupper end of the slots 55 in the frame 25, and the pushbutton 7 togetherwith the control rod 57 are likewise moved to their 0E position in whicha lateral projection on the control rod 57 engages upon the pivot pin 54of lever 36. When the circuit breaker as shown in FIGURES 3 and 4, thislateral projection of the control rod 57 is likewise in engagement withthe pivot pin 54.

In the event that a short circuit occurs, the electromagnet 10 to 15will be energized so that the arm 16 of armature 17 will be attractedand effect the release of the circuit breaker in the same manner asabove described.

If the circuit breaker is to be switched off by hand, both manualrelease knobs 8 and 9 must be shifted simultaneously toward thepushbutton 7. By the movement of the knob 9, its pin 29 slides along theinclined slot 67 in one arm of the two-armed lever 65 and therebypivot-s the latter in the clockwise direction, as seen in FIGURE 7, tothe position as shown in FIGURE 8, in which the end surface 66 of theother arm of lever 65 is located outside of the path of movement of pin29 of the release knob 8 so that this knob may then be moved in thedirection toward the other knob 9, whereby the pin 29 on knob 8 willpivot the side wall 28 of armature 17 so that its other side wall 26will be disengaged from the pawl 27 and the circuit breaker will bereleased to its off position.

When the circuit breaker is in its off position as shown in FIGURES 5and 6, the projection 58 on the control rod 57 is located within thepath of movement of the recesses 42 in the lugs 41 of lever 36.Therefore, when the pushbutton 7 is depressed and moved from the fulllmeposition according to FIGURE 5 to the position as shown in dot-and-dashlines, the projection 58 on the control rod 57 will engage into therecesses 42 and take along the two-armed lever 36 to the position asshown in dotand-dash lines in FIGURE 5. The pivot pin 54 of lever 36then acts upon the projections 35 on pawl 27 and thereby pivots thelatter in the clockwise direction to the positronas indicated indot-and-dash lines in FIGURE 5, in which under the action of the torsionspring 31 the side wall 26 passes underneath and holds thepawl 27. Ifthe finger is then taken off the pushbutton 7, pivot pin 54 of lever 36will be applied against the detents 34 of pawl 27. As soon as theprojection 58 on the control rod 57 disengages from the recesses 42 inthe lugs 41 of lever 36, the action of the compression spring 38 causesa rapid pivoting movement of lever 36 in the clockwise directron,whereby the slide member 46 together with the contact bridge are pivotedagainst the action of the release spring 46' to the on position asillustrated in FIGURE 3. The overload circuit breaker according to theinvention is :herefore movable instantaneously to the on and offposiions.

The circuit breaker as illustrated may be employed for heavy-dutyoperation for rated currents of to 400 amperes and short-circuitcurrents up to 10,000 amperes at a direct-current voltage of about 30volts.

Although my invention has been illustrated and described with referenceto the preferred embodiments thereof, I wish to have it understood thatit is in no way limited to the details of such embodiments but iscapable is in its on position,

one of said conductors being bent at a point spaced from its contact soas to form a substantially Q? -shaped loop, said magnet core beingmounted within said loop and being connected in parallel to said bimetalstrip, a cOntact bridge, means :for moving said contact bridge withinsaid housing in a direction vertical to said plane for connecting saidcontact bridge simultaneously with said contacts and for disconnectingthe same simultaneously therefrom, and a two-armed lever located betweensaid loop and said contact bridge, means for connecting said pushbuttonto said lever when said pushbutton is being depressed, stationarysupporting means within said housing having guide slots thereinextending in the direction of movement of said pushbutton, said leverhaving a pivot pin pivotable within said slot-s and slidable therein insaid direction of movement of said pushbutton, a spring acting upon thefirst arm of said lever at the side thereof facing said loop, and a pawlpivotably mounted in said housing and adapted to engage upon said pivotpin to arrest said lever in a position in which the second arm of saidlever at the side thereof facing said contact bridge presses saidcontact bridge under the action of said spring against said twocontacts.

2. An overload circuit breaker as defined in claim 1, in which, whensaid pawl is in its arresting position, it engages directly upon saidarmature which is acted upon by said bimetal strip.

3. An overload circuit breaker as defined in claim 1, further comprisinga control rod secured to said push button and movable therewith andhaving a catch thereon, said first arm of said lever having at least oneprojection thereon extending toward said conductors and having a recesswhich, when said contact bridge is in its on position in connection withsaid contacts, is located outside of the path of movement of said catch,said control rod having a longitudinal slot, said pawl having a pivotpin mounted in a fixed position in said housing and engaging into saidslot so as to guide said control rod, a stationary stop member in saidhousing, said first arm engaging upon said stop member when said contactbridge is in its off position, said recess in the projection of saidfirst arm then being located within the path of movement of said catch.

4. An overload circuit breaker as defined in claim 1, in which saidmeans for moving said contact bridge comprise a slide member secured tosaid contact bridge and adapted to guide the same in said verticaldirection, a second spring acting upon said slide member and tending tomove said contact bridge to its off position and said slide memberhaving an aperture, said second arm of said lever engaging upon thelower end of said aperture against the action of said second spring whensaid contact bridge is in its on position, said second arm engaging uponthe upper end of said aperture under the action of said first springwhen said lever is moved to its ofi" position.

5. An overload circuit breaker as defined in claim 1, in which saidhousing consists of insulating material and comprises a base and a cap,said stationary supporting means comprising a metal frame within saidhousing, an insulating plate secured to the upper side of said framefrom which said pushbutton projects through said cap toward the outside,and bolts securing said insulating plate and also said conductors tosaid base.

6. An overload circuit breaker as defined in claim 5, further comprisinga pair of knobs slidably mounted on said insulating plate at theopposite sides of said pushbutton and adapted to be moved substantiallysimultaneously in opposite directions to each other vertically to theaxis of said pushbutton for manually releasing said circuit breaker toits off position, each of said knobs having a pin thereon projectingtoward the inside of said housing, the pin on the first of said kno'bsadapted to act upon said armature when said first knob is moved in thedirection toward the second knob, a second two-armed lever on saidinsulating plate pivotable about the axis of said pushbutton, a springacting upon said second lever and tending to maintain the same in aposition in which an end surface of the first arm of said lever islocated within the path of movement of the pin on said first knob so asto prevent said first knob from being moved toward the second knob, thesecond arm of said second lever having an inclined slot into which thepin on said second knob engages so that when said second knob is movedtoward said first knob, said pin thereon slides along said inclined slotand thereby pivots said second lever to a position in which said firstarm of said second lever is located outside of the path of movement ofsaid pin on said first knob so that said first knob may then be moved soas to act upon said armature.

7. An overload circuit breaker as defined in claim 6, in which saidelectromagnetic means further comprise a magnet yoke mounted on saidmagnet core so as to be pivotable only with considerable friction, saidarmature forming a third two-armed lever having one arm which, when saidarmature is in its attracted position, nearly closes the magneticcircuit between said magnet core and said magnet yoke, the other arm ofsaid third lever being substantially U-shaped so as to have two oppositeside Walls, one of said side walls being adapted to hold said pawl inits arresting position, and the other side wall adapted to be acted uponby the pin on said first knob when being moved toward said second knob.

References Cited by the Examiner UNITED STATES PATENTS 1,912,109 5/1933Van Valkenburg et al 200l16 2,895,023 7/1959 Ellenberger 200 882,952,757 9/1960 Ellenberger 200-116 BERNARD A. GILHEANY, PrimaryExaminer,

E, SPRINGBORN, Assistant Examiner,

1. A PUSHBUTTON-CONTROLLED OVERLOAD CIRCUIT BREAKER FOR HIGH RATEDCURRENTS HAVING A HOUSING, A PUSHBUTTON SLIDABLY MOUNTED IN SAID HOUSINGAND PROJECTING TO THE OUTSIDE THEREOF, THERMAL RELEASING MEANS IN SAIDHOUSING COMPRISING A BIMETAL STRIP, ELECTROMAGNETIC RELEASING MEANS INSAID HOUSING COMPRISING A MAGNET CORE AND AN ARMATURE, TWO CURRENTCONDUCTORS ADAPTED TO BE CONNECTED TO AN ELECTRIC CIRCUIT AND HAVINGCONTACTS THEREON WITHIN SAID HOUSING AND DISPOSED WITHIN A COMMON PLANE,ONE OF SAID CONDUCTORS BEING BENT AT A POINT SPACED FROM ITS CONTACT SOAS TO FORM A SUBSTANTIALLY $ -SHAPED LOOP, SAID MAGNET CORE BEINGMOUNTED WITHIN SAID LOOP AND BEING CONNECTED IN PARALLEL TO SAID BIMETALSTRIP, A CONTACT BRIDGE, MEANS FOR MOVING SAID CONTACT BRIDGE WITHINSAID HOUSING IN A DIRECTION VERTICAL TO SAID PLANE FOR CONNECTING SAIDCONTACT BRIDGE SIMULTANEOUSLY WITH SAID CONTACTS AND FOR DISCONNECTINGTHE SAME SIMULTANEOUSLY THEREFROM, AND A TWO-ARMED LEVER LOCATED BETWEENSAID LOOP AND SAID CONTACT BRIDGE, MEANS FOR CONNECTING SAID PUSHBUTTONTO SAID LEVER WHEN SAID PUSHBUTTON IS BEING DEPRESSED, STATIONARYSUPPORTING MEANS WITHIN SAID HOUSING HAVING GUIDE SLOTS THEREINEXTENDING IN THE DIRECTION OF MOVEMENT OF SAID PUSHBUTTON, SAID LEVERHAVING A PIVOT PIN PIVOTABLE WITHIN SAID SLOTS AND SLIDABLE THEREIN INSAID DIRECTION OF MOVEMENT OF SAID PUSHBUTTON, A SPRING ACTING UPON THEFIRST ARM OF SAID LEVER AT THE SIDE THEREOF FACING SAID LOOP, AND A PAWLPIVOTABLY MOUNTED IN SAID HOUSING AND ADAPTED TO ENGAGE UPON SAID PIVOTPIN TO ARREST SAID LEVER IN A POSITION IN WHICH THE SECOND ARM OF SAIDLEVER AT THE SIDE THEREOF FACING SAID CONTACT BRIDGE PRESSES SAIDCONTACT BRIDGE UNDER THE ACTION OF SAID SPRING AGAINST SAID TWOCONTACTS.